Circuit interrupter



July 10, 1956 F. BENEDIK CIRCUIT INTERRUPTER 2 Sheets-Sheet 1 Filed Nov.4, 1952 FIG. 4-.

FIG. 3).

INVENTOR.

y 0, 1956 F. BENEDIK 2,754,392

CIRCUIT INTERRUPTER Filed NOV 4. 1952 2 Sheets-Sheet 2 FIGS. FIG. 6.

INVENTOR.

United States Patent CIRCUIT INTERRUPTER Fedor Benedik, New York, N. Y.

Application November 4, 1952, Serial No. 318,582

7 Claims. (Cl. 200-422) The present invention relates to improvements inelectrical circuit interrupters, and in particular to a circuitinterrupter of the bimetallic type adapted to interrupt a pair ofelectrical circuits alternately and successively.

The invention finds particular application in the so called electriclamp flasher which contains a bimetallic element connected Within thecircuit of the lamp and adapted to act as a switch for automaticallylighting and extinguishing the lamp. it has hitherto been attempted todevise a simple circuit interrupter which could be incorporated in thecircuits of a pair of lamps and operate to illuminate and extinguishboth lamps alternately. Need for such an arrangement is manifest inadvertising displays or the like, where alternately blinking lights tendto catch the eye of passersby. For such use, however, it is desirablethat the two lamps be illuminated for substantially equal periods, andthat the periods of illumination be substantially equal to the periodsof extinguishment. It is also essential that one lamp light immediatelyupon the extinguishment of the other, so that there be no overlapping ofextinguishing periods of illuminating periods.

The double-acting circuit interrupters hitherto devised have provedineifective in meeting the aforementioned requirements since most weredesigned along the lines of the conventional single-bulb flasher with acontact mounted on either side of the reciprocating bimetal in such amanner that the bimetal would meet one contact on heating, and the othercontact on cooling. Since the reciprocating travel of the conventionalbimetal is, however, within an almost microscopic distance, it was apractical impossibility to adjust the minute distance between thecontacts to insure proper electrical contact with both contacts, and atthe same time to allow for operating differences caused by temperaturevariation, voltage fluctuation, etc. in other types of double-lampflashers, two lamps of unequal wattage were connected in series across aline with the bimetal adapted to short out the high voltage lamp atperiodic intervals. Such an arrangement, however, required that thewattage difference in the lamps be too large for practical commercialapplication.

I provide an improved circuit interrupter utilizing either a singlebimetal or a pair of bimetals adapted to actuate a pair of switches,each of the switches being in series with a separate lamp circuit. Theswitches are arranged for positive interaction, so that when one switchis closed, the other switch is instantaneously opened.

An object of the invention is to provide a circuit interrupter of thetype described in which two lamps are in circuits independent of eachother, so that the lamps may be of equal wattage and the operation ofone lamp continues even if the other lamp is damaged or removed.

Another object of the invention is the provision of a circuitinterrupter of the type described which is operative to cause bothcircuits to be opened and closed for substantially equal periods.

Still another object of the invention is the provision of a circuitinterrupter of the type described in which the Patented July 10, 1956alternate circuit interruption is instantaneous, that is, one circuit isopened at the same instant that the other is closed.

Other objects and advantages of the invention will be apparent in thecourse of the following specification and drawings which show apractical application of the invention by way of example, rather than ina limiting sense.

Pig. 1 is a side elevational view of the circuit interrupterincorporating a pair of bimetallic elements, with the schematic circuittherefor including a pair of lamps, and the bimetallic elements in theirunheated positions.

Fig. 2 is a side elevational view of the assembly of Pig. 1, but showingthe bimetals in their heated and flexed positions.

Fig. 3 is a side elevation of a modified form of circuit interrupterhaving a single bimetallic element which is shown in its unheatedposition.

Fig. 4 is a side elevation of the circuit interrupter of Fig. 3, withthe bimetal in its heated position.

Figs. 5 and 6 are side elevational views of another modification of asingle bimetal circuit interrupter respectively showing the bimetal inits unheated and heated positions.

Figs. 1 and 2 illustrate a preferred embodiment of the invention whichincludes a pair of flat bimetallic strips 10 and 11 rigidly mounted, asby means of rivets 14, 15 to an insulated base 12.

The bimetals 19 and 11 are preferably of the same size and shape forconvenience of manufacture, and are of the usual type which will bend orflex when heat is applied thereto. As a typical example, the bimetalsmay be made of a thin strip of brass fused flat against a thin strip ofsteel.

The bimetal it) carries a rigid insulated plate 16 and anelectrically-conductive spring element 17. The plate 16 is rigidlymounted by a rivet 18 to the top of bimetal 10 as an upstandingextension thereof. The rivet 18 also secures to said bimetal 10 one endof said spring element 17, the rivet being made of a conductive materialto electrically connect said spring element 17 to said bimetal 10.

The spring element 17 is made of a thin strip of flexible and resilientmaterial such as Phosphor bronze and is bent to form a top bracket 19 ofinverted U-shape and an integral elongated depending arm 17a. The latteris bent upon itself to form a depending fold or bight and its free endis secured to the bimetal 1t) and plate 16 by the rivet 18. T he foldedarm 17a enhances the resiliency of the spring element 17 to permit aspringy motion of the bracket 19 relative to the plate 16.

The bracket portion 19 of element 17 presents two spaced parallel armswhich carry respective electrical contacts 20 and 21. These contactsface in the same direction, namely the direction in which the bimetal 10will bend when heat is applied thereto, or to the right in Figs. 1 and2. The insulated plate 16 has secured thereto a contact 22 which facescontact 20 and is normally urged into engagement therewith by thetension of the resilient element arm 17a. A contact 23 is fixed to thetop end of bimetal 11, and is also electrically connected thereto. Saidcontact 23 faces the contact 21 and is normally spaced from contact 21when the bimetals 10 and 11 is in its straight unflexed position of Fig.l. Contact 22 is insulated from the bimetal 10 by the plate 16, andcarries a connecting lug 24 electrically-connected by a lead wire 25 toa terminal 26 which may be in the form of a rivet secured to the base12. The rivets 14 and 15 previously mentioned, may also be designated asterminals.

The bimetals 10 and 11 are covered by layers of insulation 26 such asasbestos, mica, or the like. A heater coil 28, which may be made ofNichrome wire, is wound around the insulation of bimetal 10. A similarheater coil 29 is wound around the insulation of bimetal 11.

One free end of the heater coil 28 is electrically connected to the bodyof bimetal 10, the other end thereof being electrically connected to theterminal 14. Similarly the free ends of heater coil 29 are respectivelyelectrically connected to the body of bimetal 11 and to the terminal 15.Thus in the electrical circuit of the unit, both heater coils 28 and 29are in effect connected in parallel between the conductive bodies ofboth bimetals and 11.

As shown schematically in the drawings, the terminal 14 is adapted to beconnected by a wire 31) to the terminai 31 of a power line which maycarry the normal 110 volt A. C. or D. C. line current. The other powerline terminal 32 may be connected to terminal 15 by a wire 33. Terminal26 is also connected to power line 31 by a Wire 35. The wires 30 and 35are in series with respective electric lamps 34 and 36.

Since the heater coils 23 and 29 are wired in parallel between thebimetals 10 and 11, these two coils will heat simultaneously when linecurrent is supplied through terminals 31 and 32. To actuate heater coil28, current supplied through wire 33 flows through terminal 15, bimetal10, thence through heater coil 28 to terminal 14 and through wire 30 andlamp 34 to power line terminal 31. Current from wire 33 also passesthrough heater coil 29 and through bimetal 11, terminal 14 and wire 30to power Iine'terminal 31. Although current flowing through Wire 30passes htrough the filament of lamp 34, the lamp 34 does not light sincethe heater coils 28, 29 are in series therewith and dissipate thegreater part of the current in heating. Current also flows through aparallel circuit through wire 33, bimetal 10, rivet 18, spring element17, the closed contacts 20, 22, wire 25, terminal 26, wire 35 and lamp36, lighting said lamp 36.

When the coils 28 and 29 are energized, the bimetals 10 and 11 arequickly heated so that they begin to bend toward each other. The bendingof bimetal 10 toward the right from its position of Fig. 1 carries theattached plate 16 and spring element 17 toward bimetal 11, while at thesame time, bimetal 11 is bending to the left and toward spring element17. The contacts 21 and 23 are thus brought into firm pressingengagement which in turn pushes bracket 19 to the left relative to theplate 16 and against tension of the spring arm 17a. Movement of thebracket 19 relative to plate 16 immediately separates contacts 20 and 22which remain spaced from each other as long as contacts 21 and 23 are inengagement.

Immediately upon separation of the contacts 20 and 22,

the circuit through lamp 36 is opened and said lamp 36 is extinguished.At the same time another circuit is closed by the engagement of contacts21 and 23, this circuit leading through wire 33, terminal 15, bimetal10, rivet 18, spring element 17, the closed contacts 21, 23, bimetal 11,terminal 14, wire 30, and lamp 3'4, lighting the latter. It will benoted that this circuit shorts out the heater coils 28 and 29, so thatthe current bypasses said coils and the bimetals 1t) and 11 are allowedto cool while contacts 21 and 23 are closed.

As the bimetals 119 and 11 cool, they straighten from their bentpositions of Fig. 2 until the contacts 21 and 23 separate, at Which timethe spring arm 17a returns the bracket to its original position of Fig.1 relative to the plate 16 and the contacts 20 and 22 are again broughtinto engagement. These heating and cooling cycles are repeatedautomatically -so that the lamps 34 and 36 are successively andalternately lighted and extinguished.

The-lamp 36 is thus lighted during the heating period of the bimetals 10and 11, while the lamp 34 is lighted during the cooling period of saidbimetals. To maintain a substantially uniform illuminating period forboth lamps, the bimetals 1t} and 11 are made in such a manner that theircooling period is substantially equal to their heating period. This maybe accomplished bysuch Wellknown expedients as selecting suitablebimetal dimensions and component bimetal materials, varying the length,resistance, or pitch of the heater coils, etc.

The embodiment shown in Figs. 1 and 2 in which a pair ofoppositely-bending bimetals are utilized presents distinct advantages.The opposed movement of both bimetals 1t) and 11 insures sharp andpositive meeting and breaking of the contacts. In addition thisembodiment is of particular application when a rapid alternate flashingof the lamps is desired since the combined movement of both bimetalstoward each other reduces by approximately half the time required forthe same operation by a single bimetal. However, if desired for the sakeof economy of manufacture, or if extremely rapid flashing is notdesired, either of the two bimetals 10 or 11 may be eliminated withoutimpairing the operative efiectiveness of the unit. Figs. 3 and 4 show asimilar unit in which the bimetal 11 is eliminated while Figs. 5 and 6show a unit in which bimetal 10 is eliminated. Both of these units havean identical mode of operation.

In the flasher unit shown in Figs. 3 and 4, the base 41 has an elongatedupstanding extension arm 41a which replaces the bimetal 11. A bimetal 4Qwhich is identical with the bimetal 11) of Figsl and 2 is mounted onbase 49 by means of a rivet terminal 4-2. Bimetal 40 carries aninsulated plate 44 an the bent leg of a spring element 45 which aresecured thereto by a rivet 43. The spring element top bracket 46 has apair of contacts 47 and 43 which are mounted to face in the samedirection. A contact 49 mounted on plate 44 faces contact 47 and isnormally maintained in engagement therewith by the tension of theresilient bent leg of element 45. Contact 49 carries a connection lug 56which is connected by wire 51 to a terminal rivet 52.

The upstanding base arm 41a has fixed contact 53 which faces contact 48and is connected by a lug 54 and wire 55 to a terminal rivet 56.

The bimetal 413 is covered by a layer of insulating material 57, aroundwhich is wrapped a heater coil 53. One end of the latter is connected tothe body of bimetal 40, while the other end is connected to terminal 56.

The terminal 42 is connected directly to a power source terminal 5?through a wire 60. The other power source terminal 61 is connected toterminal 56 through a lead 62 in which a lamp 63 is connected. Terminal52 is also connected to the power source terminal 61 by a wire 64 whichalso leads through a lamp 65.

When the bimetal is in its normally straight position of Fig. 3, thecontacts 47 and 43 are in engagement, and current flows from the powerterminals 59, 61 through a circuit formed by wire 6%, terminal 42,bimetal 40, heater coil 53, terminal 56, wire 62, and lamp 63; heatingthe coil 58, but leaving the lamp 63 unlighted. At the same time currentflows through a parallel circuit formed by wire 6%, terminal 42, bimetal40, rivet 43, spring element 45, contacts 47 and 49, lug 50, wire 51,terminal 52, and lamp 65; lighting said lamp 65.

As the bimetal 41 is heated by coil 53, it bends toward the base leg 41auntil contacts 48 and 53 meet. The bending force of bimetal 4t) pressescontacts 48 and 53 together, thereby moving the top bracket 46 relativeto the bimetal 4i) and separating contacts 47 and 49, as shown in Fig.4. The circuit through lamp 65 is thus opened. At the same time, theengagement of contacts 48 and 53 closes a circuit through lamp 63, thecurrent flowing through wire 66, bimetal 4t) and its connected springelement 45, across the closed contacts 48, 53, and through wires 55 and62 through the lamp 63 to light the latter. This circuit shorts out theheater coil58, so that the heater coil 58 and bimetal 40 are cooledwhile the contacts 48, 53 are in engagement.

After the bimetal 45 has cooled sufliciently, it straightens and allowsthe contacts 48 and 53 to separate, thereby causing the resilience ofspring element 45 to urge the contact 47 into engagement with thecontact 49, and the flashing cycle is repeated.

In the flasher shown in Figs. 5 and 5, the bimetal 10 of Figs. 1 and 2is eliminated. This flasher has a base 70 which has an upstanding leg70a. To the lower end of the latter is secured a spring element 71 bymeans of a rivet 72 which also serves as a terminal. The spring element71 has an elongated resilient arm 73 which is integral with a topU-shaped bracket 74, the latter having secured thereto a pair ofcontacts 75 and 76. Contact 75 faces a contact 77 mounted on the baseleg 70a and is normally urged into engagement with said contact 77 bythe resilient element arm 73. Contact 76 faces a contact 78 which issecured to a bimetal 79 mounted 011 a base 7 by a rivet 80 which alsofunctions as a terminal.

The bimetal 79 has an insulated covering 81 around which is wound aheater coil 82 whose ends are respectively connected to the body ofbimetal 79, and to terminal 72.

Contact 77 carries a lug 83 which is connected by a wire 84 through alamp 86 to a power terminal 85. Terminal 72 is connected by a wire 87 tothe other power terminal 88. Terminal 80 is connected by a wire 90 tothe power terminal 85, the wire 80 having a lamp 91 connectedintermediate its ends.

The circuits shown in Figs. and 6 are identical in operation to that ofthe flasher illustrated in Figs. 3 and 4, and will not be described indetail. When the device is in the normal position shown in Fig. 5, thelamp 86 is lighted and the coil 82 is heated causing the bimetal '79 toflex in the direction of the spring element 71. When the contacts 76 and78 engage, the pressure of the bimetal 79 upon the resilient springelement 71 causes the bracket 74 to move to the left to its positionshown in Fig. 6 in which the contacts 75 and 77 are separated. In thisposition, the lamp 91 is lighted while the circuits through lamp 86 isbroken and the heater coil 82 is short circuited.

In Figs. 1 and 2, the contacts 20 and 22 may be designed as a firstswitch and the contacts 21 and 23 may be designated as a second switch,the first switch regulating the circuit through lamp 36 and the secondswitch regulating the circuit of the lamp 34. The switches are actuatedby the coaction of the bimetals and 11 with the spring element 17 in themanner of a single-pole, double-throw switch. Similarly, in theembodiments of Figs. 3 and 5, the respective pairs of contacts 47, 49and 75, 77 may be designated as first switches, while the respectivepairs of contacts 48, 53 and 76, 78 may be designated as secondswitches.

While preferred embodiments of the invention have been shown anddescribed herein, it is obvious that numerous alternations, omissionsand additions may be made Without departing from the spirit and scope ofthe invention. In particular, it is to be understood that the use of theinvention is not to be limited to the illumination of elecric lamps, butthat other types of electrical circuits may be effectively regulatedthereby.

What is claimed is:

l. A lighter flasher for successively and alternately lighting andextinguishing a pair of electric lamps, said flasher comprising a base,an insulated member mounted on said base, a U-shaped bracket memberhaving a pair of spaced parallel arms and a resilient extention leg,connected to said insulated member, a bimetallic member mounted on saidbase and being adapted to flex in the direction of said bracket memberin the presence of applied heat, a first and second electrical contactrespectively mounted on the parallel arms of said bracket member andfacing in the some direction, a third electrical contact mounted on saidinsulated member and facing said first contact, a fourth electricalcontact mounted on said bimetallic member and facing said second contasaid resilient extension leg normally urging the bracket member to aposition in which said first and third contacts are in engagement andsaid second and fourth contacts are spaced from each other, said bimetalbeing bendable when heated to press the fourth contact against saidsecond contact and move said bracket meniber to a position in which saidfirst and third contacts are brought out of engagement, an electricalheater element mounted proximate to said bimetal for supplying heatthereto and connected across said second and fourth contacts, means forconnecting a first electrical lamp circuit in series with said first andthird contacts, means for connecting second electrical lamp circuit inseries with said second and fourth contacts, and a third electricalcircuit through said heater element, said third circuit being inparallel to said first circuit, said second circuit shorting out saidthird circuit.

2. A light flasher according to claim 1 in which a second bimetallicmember is also mounted on said base, said bimetal carrying saidinsulated member and being adapted to bend in the direction of saidfirst bimetallic member in the presence of applied heat and carry saidbracket toward said fourth contact.

3. A light flasher according to claim 2 in which a second heater elementis associated with said second bimetallic member, said second heaterelement being wired in parallel to said heater element.

4. In an automatic circuit interrupter, a spring member, an insulatedsupport mounting said spring member and having a contact insulated fromsaid spring member, said spring member having an elongated spring armconnected at its end to said support, said spring arm extending abovesaid support and terminating in a lateral leg extending across the topof said support, said lateral leg terminating in a depending legparallel to the spring arm, the depending leg and the spring armbracketing the support member, said depending leg having a contact whichfaces and is alined with the contact of the support, the spring arm alsohaving a contact facing in the same direction as said depending legcontact, the resilience of said spring arm urging the depending legcontact into pressing engagement with said support contact, a fourthcontact facing said spring arm contact and normally spaced therefrom,and a heat responsive member movable to bring said fourth contact andsaid spring arm contact into pressing engagement, thereby causing saidspring arm to flex and separate said depending leg contact from thecontact of said insulated support.

5. A device according to claim 4 in which a heater coil is mounted inproximity to said heat-responsive member, said heater coil beingconnected across the fourth contact and the spring arm contact.

6. In an automatic electric light flasher for successively andalternately flashing a pair of lamps, a support base, first and secondbimetal elements mounted on said base parallel to and spaced from eachother and adapted to flex toward each other in the presence of appliedheat, said bimetals each having an electrical contact, the contactsfacing in the same direction, a conductive spring arm mounted on thefirst bimetal and movable therewith, said spring arm havin a head ofinverted U-shape having a pair of parallel arms bracketing the firstbimetal, the arms having respectively a third and fourth electricalcontact facing in the same direction and positioned to contactrespectively the first and second bimetal contacts, said spring armbeing resilient and normally urging said first and third contacts intopressing engagement, the second bimetal being positioned in unflexedposition with its contact spaced from the fourth spring arm contact, andheater elements for said bimetals connected across said second andfourth contacts to be shorted out when said second and fourth contactsare closed and to be energized when said second and fourth contacts areopen, said heater elements when energized being adapted to heat saidbimetals sufiiciently to cause movement thereof to positions in whichthe second and fourth contacts are closed and the first and thirdcontacts are opened.

7. In an automatic electric light flasher for successively andalternately flashing a pair of lamps, a support base, first and secondbimetal elements mounted on said base parallel to and spaced from eachother and adapted to flex toward each other in the presence of appliedheat, said bimetals each having an electrical contact, the contactsfacing in the same direction, a conductive spring arm mounted on thefirst bimetal and movable therewith, said spring arm having a head ofinverted U-shaped having a pair of parallel arms bracketing the firstbimetal, the arms having respectively a third and fourth electricalcontact facing in the same direction and positioned to contactrespectively the first and second bimetal contacts, said spring armbeing resilient and normally urging said first and third contacts intopressing engagement, the second bimetal being positioned in 'unfiexedposition with its contact spaced from the fourth spring arm contact, andheater elements for said bimetals connected across said second andfourth contacts to be shorted out when said second and fourth contactsare closed and to be energized when said second and fourth contacts areopen, said heater elements when energized being adapted to heat saidbimetals suificiently to cause movement thereof to positions in whichthe second and fourth contacts are closed and the first and thirdcontacts are opened, and means for attaching a lamp in series with saidfirst and third contacts and a lamp in series with said second andfourth contacts.

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